Magnetic and transport behavior of electron-doped<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">La</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mi>−</mml:mi><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Mg</mml:mi></mml:mrow><mml:mrow><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">MnO</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mi/><mml:mo>(</mml:mo><mml:mn>0.45</mml:mn><mml:mn/><mml:mo><~</mml:mo><mml:mi>x</mml:mi><mml:mo><~</mml:mo><mml:mn>0</mml:mn><mml:mo>.</mml:mo><mml:mn>6</mml:mn><mml:mo>)</mml:mo></mml:math>
Bibliographic record
Abstract
Detailed measurements of the linear and nonlinear magnetic responses, the zero-field cooled and field-cooled magnetization, and the resistivity of electron-doped ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Mg}}_{x}{\mathrm{MnO}}_{3},$ $0.45<~x<~0.6,$ are summarized. For $0.05<~x<~0.6$ this system exhibits a single paramagnetic to ferromagnetic phase transition on cooling with no thermodynamic reentrant transition to a spin-glass-like phase. Nevertheless, both a detailed analysis of the critical response and the low temperature saturation moment show clear evidence of competing interactions. The latter could arise either as a result of spontaneous electronic phase separation or from conventional noncollinearity (homogeneous, or---due to the random substitution process---inhomogeneous). These results argue against a simple double exchange picture for this system and a uniform ferromagnetic ground state. However, features evident in the zero-field-cooled behavior (and the nonlinear response) at temperatures below ${T}_{c}$ originate from technical sources viz. the increase in coercive field, so it is possible that a gradual onset of competing interactions might arise from a related source. The resistivity data confirm that the complete suppression of a metal-insulator transition in these systems with small average A-site radius extends into the electron-doped regime $(x>~0.5).$ Thus ferromagnetism dominates but the system remains insulating, contrasting with an emerging ferromagnetic metallic state for which a spontaneous electronic phase-separation approach has been proposed. Indeed, the transport data conform with model expressions for charge transport by nonadiabatic small polarons in the paramagnetic phase, but they are quantitatively inconsistent with the expression derived recently by Rahkmanov et al. [Phys. Rev. B $63,$ 174429 (2001)] for the specific model of polaronic hopping in a nonmetallic, phase separated picture.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.011 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".